The present invention relates to an electric compressor and a method for manufacturing the same.
There has been provided an air conditioner for a vehicle having an electric compressor that is fixed through a supporting member to a body of the vehicle in an engine compartment of the vehicle. Japanese Patent Application Publication No. H05-77640 discloses a structure in which a compressor is mounted to a vehicle through support legs and a mounting plate. The support legs are fixed by circumferential welding to the compressor at a position adjacent to the center of gravity of the compressor and have therein a hole for receiving therein a rubber mounting. The mounting plate is fixedly connected to the vehicle and has a hole through which the compressor is inserted. The support legs fixed to the compressor are fixedly connected to the mounting plate by bolts with washes. Thus, the compressor is mounted to the vehicle body through the support legs, the rubber mounting and the mounting plate. The above-described structure prevents the compressor from being vibrated largely by external vibration applied to the mounting plate of the vehicle body while the vehicle is traveling.
In the background art disclosed by the above-cited Publication, however, if the resonance frequency of the rubber mounting (vibration damping member) coincides with the vibration frequency of the compressor, the amplitude of vibration of the compressor is increased and the increased vibration is transmitted through the support legs to the mounting plate of the body of the vehicle, with the result that noise development in the passenger compartment of the vehicle is increased. As a measure to solve this problem, it may be contemplated to provide a vibration damping member having a resonance frequency that is different from vibration frequency of the compressor. However, the vibration of the compressor and the vehicle has vibration frequency components over a wide range of frequencies. Therefore, merely changing the resonance frequency of the vibration damping member is unable to prevent the compressor from being vibrated under the influence of resonance.
The present invention, which has been made in light of the above problems, is directed to providing an electric compressor that suppresses vibration of the electric compressor by providing vibration damping members whose resonance frequencies are changed when the electric compressor vibrates.